The Oracle Business Intelligence Cloud Service (BICS) offers various options through which data may be loaded into the BI cloud database. I am focusing here on BICS that comes with the Database Schema service as a reporting database. In addition, there are several ways through which you may extract data from BICS. It may be confusing to know which approach needs to be followed and therefore I am listing the most important characteristics of these approaches on the slides below. This should help in figuring out which approach for data loading and extraction works best for your situation.
A quick walkthrough of the different BICS data loading techniques is available at the following YouTube recording: https://youtu.be/25QEQyw_iXU
If your BICS is connected to the Oracle Database as a Service (DBaaS) as opposed to the Database Schema Service, all these methods are still applicable but you will also have several other options as well in that case such as leveraging ETL tools like Oracle Data Integrator (ODI) or Informatica Cloud.